Updated: Aug 14, 2020
Lots of classes say they offer strength training, but the reality is you’re HIIT class isn’t placing the proper stimulus on your neuromuscular system to elicit a true strength response.
To understand strength training we need to understand one of the staple concepts in the fitness world. The SAID principle. The SAID principle, or principle of specificity, states that the body will adapt to the specific demands that are placed on it. When we apply this principle to resistance training (weight training) we need to think about the fibers our muscles are composed of. Some of you may have heard of slow and fast twitch muscles but what is the actual difference? To start each individual muscle contains some combination of both type I and II fibers. Type I fibers (slow twitch) are actually smaller in diameter making them much slower to produce maximal force than their type II counter parts. The tradeoff is that type I fibers are much more resistant to fatigue. Each fiber type must be specifically targeted through proper training manipulations to elicit their recruitment. When we train our type I fibers we may still be using weights but the adaptation is actually considered muscular endurance, the ability to produce and maintain force production for a prolonged period of time. It isn’t until we force those type II fibers to get to work that we are able to train strength. Training both muscular endurance and muscular strength required to get the full benefits of resistance training.
So that “strength” training HIIT class you go to may have dumbbell squats as part of their programming. When it comes time to select your set of dumbbells, you’re going to select a lighter pair because you’ll have to preform the squats for a full 40-60 seconds racking up 15-20 reps per set. This is a prime example of working those type I fibers and training muscle endurance. Your brain recognizes that the weights you selected are relatively light to what you are capable of handling. It, always trying to conserve energy, leaves your type II fibers alone. Do only this kind of training long enough and your brains capacity to recruit those neglected type II fibers will start to disappear altogether. You may get really good at squatting that set of dumbbells for higher and higher reps, but when you go to make the jump to a higher weight don’t be surprised if your muscles and brain don’t have the capacity to do so. Like I said, muscle endurance is very important and needs to be part of training, but it can’t be the only stimulus we place on ourselves. By doing so we leave lean mass and strength gains on the table. Those lean mass and strength gains are what leads to a higher metabolic rate (burning more calories throughout the day), greater bone density as we age, greater neuromuscular control (coordination), and strength capacity itself is one of the most accurate indicators of mortality.
This means that you have to be using the heavier weights (Like our member Kayla above). Now, I’m not saying you need to start training for a power lifting meet but heavy compound exercises need to be incorporated into your weeks workouts. To elicit a true strength adaption, you need to be handling weight at least 85% of your max capacity during your multi-joint lifts like the dead lift, squat, and pressing movements (i.e. dips, bench, and/or overhead presses). That means rep ranges are going to be smaller, and rest periods are going to be longer. A proper rep range for strength can be anywhere from 1-6 (5-6 for beginners still gaining competency with the movements and body control, and 1-4 for intermediate to advanced lifters able to keep body integrity as they go closer to their max weight) for 3-4 sets, resting around 3 minutes in-between. Without the proper rest period we don’t allow are body to fully regenerate ATP (your bodies energy). If we rush into another heavy set with depleted ATP we won’t be able to produce the proper amount of force required to become stronger. Before you freak out about not burning enough calories (it’s actually not super relevant but that would make this blog double the size so it’ll be for another time) you can still get your heart rate up after because this should really only take 20-25 minutes. Strength training is for everyone because it benefits everyone. It’s time to stop pretending that air squats and planks are developing a strong body. To be well rounded and equipped for what the sport of life could throw at us grab that heavier set of dumbbells, load up a barbell for the first time, and remember that it’s not about trying to be the strongest in the gym but becoming a stronger you.